1. Field of the Invention
This invention relates to the field of dampers installed between structural and non-structural members of a building to absorb vibrational energy impact to the members caused by seismic tremors and/or high winds.
2. Description of the Prior Art
Prior art dampers include frictional devices, viscous devices, hydraulic devices, and elasto-plastic devices. Among these dampers, the elasto-plastic damper tends to be the most commonly used because this damper is easy to maintain, has the physical property of non-destructive repetitive use, and is capable of great energy absorbability.
To function, the commonly used prior art elasto-plastic damper primarily depends on the relative displacement between an upper structure and a lower structure, or the relative displacement between any story in the structure and the adjacent stories above and/or below the intermediate story. Elasto-plastic dampers utilizing relative displacement require space between the upper and lower members, and space available to install such dampers is usually limited. Prior art dampers are illustrated in U.S. Pat. No. 4,901,486 to Kobori et al., which discloses elasto-plastic dampers of various configurations which require considerable mounting space. The mounting means are relatively complex and time consuming to secure.